The present invention relates to an X-ray exposure system and, more particularly, to an X-ray exposure system effective for proximity exposure in which a mask circuit pattern and a wafer circuit pattern are aligned at a high accuracy and the mask circuit pattern is exposed on the wafer, or for projective exposure.
An X-ray exposure system of such a kind as illustrated in FIG. 1 is disclosed in Japanese patent publication No. 53-34466 and in S. Yamazaki et al., "Development of a High-precision X-ray Exposure System", Seimitsu Kikai, Vol. 46, No. 4, PP. 79-84 (1980).
As illustrated in FIG. 1, the known X-ray exposure system comprises a frame 2 placed on the floor with vibration isolators 11 therebetween, an X-ray source 3 fixedly mounted on the frame 2, a mask alignment system 9 for aligning a mask 6 and a wafer 7, and a bed 10 supporting the mask alignment system 9 thereon and placed on the floor with vibration isolators 11 therebetween.
The X-ray source 3 radiates X-rays from a fixed X-ray generating point on a rotary cathode 4 onto the mask 6 to expose a mask circuit pattern on the wafer.
The mask alignment system 9 is mounted on the bed 10 and the bed 10 is supported on the vibration isolators 11 so that vibration will not be transmitted from the floor to the mask alignment system 9 and vibration of the rotary cathode 4 of the X-ray source 3 will not be propagated to the mask alignment system 9.
However, this known X-ray exposure system takes no notice of the relative dislocation between the X-ray source and the mask alignment system attributable to the positional instability of the bed due to the vibration of the vibration isolators 11.